Telephone-exchange system



T. VAN AMSTELI TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 3, X919.v

Patented Apr. 20, 1920.

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T. VAN AMSTEL.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION man FEB. a, m9.

1,337,736. Patented pr. 20, 1920.

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.30 -switches under the control 'of a sending de- UNITED sTATEs PATENT oEEicE.

Timon VAN unimi., or`

NEW YORK, N. VY., ASSIGNORTO WESTERN ELECTRIC COMPANY, INGOBYORATED, OF NW YGBK, N. Y., A CORPORATION F NEW YORK.

a subject of the' King of G reat Britain, naturalized Canadian, residui at 'New York, in the county of New Yor and State i of New-York, have invented certain new V,and .useful Improvements in Telephone- Exchan e Systems, of which the following is a ul clear, concise, iid exact descrip tion.

particularly to systems comprising'several ollices. of different character.

The present invention has f or vitsobiect the povisionof an improved signaling system in which ndicatm trolled by a pluralit switches over a meta lic devices are ecnc'ireuit by ulseS of various characteristics transmit over said circuit. l

'In its more specific embodiment, the` present invention is employed in airautoinatic 'telephone system in which callin lines terminating in a semi-automatic exc ange may be connected to called lines terminating at a manual exchange. -In such a systemvan o ierator at 'the semi-automatic egicliangle, a er connecting her answering cord to t e calling line, sets -one or more automatic vice to extend the calling liiie to the operators position at the manual eiicliaii :,fe.V Since there can `be lio i'rrbal communication between two such opera ors, it is then necessary in com letiifig the call to indicate the number of t e wanted'subscriber to the operator at the manual exchange.' In the present disclosure the wanted number is ,indicated by sets of lamps, a set of lamps bein provided for cach `digit-or character he wanted number.

lselectivelyoperated in response to t ie operation of a sendiii device-'which is-variably controlled byt ie operator-at the semiautoniatic exchange. Une feature of the invention consists in the control' of an indicating device by al plurality of small step-by-step switches.

This and other features of the. invention will appear ni the acminpanying drawing* and description, together with the appended claims.

Ihis invention relatesA to machine switch-` ing -telephone exchange systems and more small step-by-saip These lain )s are' TnLiirnomi-Excnancn SYSTEM.

`Specillcaitinii of Letters Patent. Patented Apr 20, 1920.

3, 1919. Serial N0. 274,758.

Thedrawing with Figure 2 placed below Fig. 1, diagrammatically represents a portion of a tele. -lione system employing the present invention- Fig.v 1 shows a calling Subscribers substation and; line, with brushes enf' a vdistrict selector at the semi-automatic peratorsposition, a calling plug and jack at the manual operators position and a called subscribers substation apparatus `and line. Within the small dotted rectangle at the left-liand side of Fi 1 there are shown "the brushes of a cord nder switch which is Voperated to Vconnect an idlefsendng dcvice to a cord circuit ivlii h has been conneet/ed to the calling line. tWithin the large dottedi'ectangle at4 the right-hand side -of lFig. 1 there are .hon'nthe operators key set. and the registers for controlling the transmission of im ulses tothe number ildicating device. l ithin the dotted inclusui'ein the middle of Fig. 1 there is shown en impulse transmitting-.device which, under the` 'control of *be registers, transmits various combinations of imp'ulses to actuv site tlie number indicating device. In Fi Q there 'is shown a' 'set of relays which is actuated bythe impulse transmitting de- .vice'and a plurality vof small step-by-step switches which' are controlled' in turn `by such.I relays. There are. also shown live sets of indicating lamps, oneset for the indication ofV the station, one setfor'the indica tion of the thousands` one set for the indication of the hundreds, one set for the indication` of the tens and another set for the' indicationY o f the units digit of the Wanted number. Fig. 3 is a table showing the code of impulses for making the numerical selections and Fig. l is a similar table showing the code of impulses for t'ioii of the stations. 1 In this-disclosure the shoiving of the'a paratus and the circuits for selecting tiie manual operators position has been abbreviated, but it may be of the character of making the selecthe system disclosed in thc patent to Lundell Xo. 1,168,319, of January 18, 1916, or 'it may be similar to the system shown in the copending `application of Clark No.'178,i68,

July 3, 1917.

The trunk selecting switch referred to in the description may be of the type illustrated in the patent toCraft and 'Reynolds No. 1,123,696 of January 5, 1915, although it will be readily understood that aml automatic selector switch can be emloyed in this system without depalting rom the s irit of the, invention.

' In the iescription, references are made to sequence switches and registers, the strut'- ture of which may be similar to that shown in theA Vatout t0 Reynolds and Baldwin No. 1,127,880f February 9, 1915.4

In general, the system comprises a set of operators keys which control sequence switch re' isteria, all of which are show 'n in the dotted rectangle at the right in Fig. 1. A. device'for sending impulses. as delermined by sequence switch registers, is shown iii the upper left-haud dotteduiwlosure ot 1, and an arrangementof relays and .small step-hy-step rswitches: for receiving these impulses is shown in Fig. 2. l

In Fig. ,2 there aro'shown three. relays 1 n Series, 201, 202 and 203 which respond dlrectly to -tbe` transmitted' impulses. 'lh'ese relays QUI, 202 and 2025 in turn controi a plul'alit Vof small 'step-bystep switches, one of whici is used as a master switch to control the sequence of operation of the others. Thereis provided a set of indicating lamps for each one of the digits of the .called number, each set of lamps being controlled by two ot the small step-b v-step switches. l

The impulses` transmitted by the device controlled by sequence switch 114 `in AFi f. 1 are in the nature of a code..J theseimpu ses being in xr discontinuous train of positive and negative impulses of light and jhea\ y current. The impulses oflight current are' produced through a grounded battery cur# rent flowing through a resistance 142 to the combination of sequence switch contacts [33 and 139. The impulses of heavy current are produced bv grounded battery current llowmg through a path which does not contain resistance. I

The code of `impulses is shown diagrammatically in the lower part of Fig. 2 under the two headines Numerical code" ainl pStationscode.v` Each code character is divided' into Sixstageg. and various num bersmf' impulses comprise each such code character. invariably. the last .stage com tains'uo impulse. Invariably. also. the last impulse of a code character is ouiI of heavyI current. It may be said thcrel'ori` that cach code elia-racial' comprises six stages. 1n cach of which .there is transmitted either no im! pulse. a lightl impulse of negative current or a light impulse ot' positii'c current` and a last impulse of either positive or negative v y d I heavy .eilrrent 1 ,In order to give a clear understaudiner of the,inv'eution. a table, presented below. has been prepared on the assumption that the 'number to he indicated is, tor example, MGT-ll". l'nsuch systems as the present, it is customary to send impulses representing the station, then the impulses representing the thousands hundreds` tens and units die'its in turn. I`he first column of the table is a tabulation of the dieit or character sent. The second column o? the table is a tabulation of the stages ot' which the entire -train of impulses is couiposcd. 'l`he third column is a tabulation of the. corrcspoiuliner positions of the sequence switch 114. The fourth column is a tabulation of the inipulses transmitted. The light impulse of negative current being represented by the mark the light impulsi` of positive current beingr indicated hythc character and the heavy impulses ol'` negative 'and positive current being indicated 'by thecharacters H-"` and I'l+." These tabulations of impulses may .be checked by the two tables" appiairingir in Fig. 2. The lil'th column is a tabulation of the pointsl at which .'lelays 201, 202 and 2ll3are operated. y'lhe examination of this table and a comparison of other columns will disclose the fact that 'relay 9.01 is actuated ,whenever an impulse 'of heavy current of either positive .or nega- '.tive character is transi'iiitted, andfhat relay 2402 is always actuatedwhen an impulse of positit'e current is transmitted, and like-V wise relay 203 is actuated when a negative impulseis transmitted. It will furthermn'e are simultaneously actuated. The sixth col-4 ,umn of this table is a tabulation ofthe po'- sitions of the master switch. .\n examination of this column will disclose the 'fact -that the master switch remains in one position until a-ll of.the. impulses representing a certain character have been transmitted and relay 201 luis been actuated. [twill furthermore disclose the fact that the master switch is stepped from o'ue position to the next upon the cessation ol a heavy impulse. `The seventh column of this table is Va tabulation of the step-hy-step switch magnets as they are operated. lt will he apparent that while the master switch is. for example. in -position l` that magnets E205 and 20u are in a'rircuit to bc actuated and are so actuated whenever relays 203 and UJ are actuated. Then .the master switch mores to position magnets QUT aud 20H are in circuit to be antuatcd. and they in turn are energized in rcspohseto the actuation of relaysv 203 ,and 202. lt so happens. in .the example taken` .that while the master switch is in position 2. relay :'fl is at no time energized and hence magnet 203 dpesnot become. energized. ln cohnnuIS there is anidication of the posilion in which the. positive lamp arm of-tli step-by-stpgwitt'h is found in the. last stage of each digit. -n likewiiiinner, column 9 Asliowsuthe position in which, the negative ke board of Tau-o lamp arm is found inthe' sixth stage of euch digit. Inthe tenth sind` hist column isiin indication of'the particuiar lamp which is reused to glow' when the positive and negii tive lamp arms have been properly postY 'tioned,

Digit. Stage. P05.

Master switch pos.

Rolo Pos i I I oper? Alaniparntnl` Lamp' Puslomp crm.

Station-W evocan-f Thousand-4 Hundred-5 ....4.....;

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isi '.1'.

It.. is believed that the iuventionwill be more clearly understood from the following detailed description of the method of estab lishing a connection of n calling substation' asfshown at 101 to a cul1ed`substntion .as shown at 4567-\V. ,fwhen the calling sub-I sci'ilier'remo-res his receii'er from his Switchhook, Viisigriiiltnot shown) is lighted at the semi-automatic opei'utoi"s` position. operato'r thereupon -connects the cord circuit conductors 1.03.and 104 to the calling line. manually or by any other suitable, means. As soon asthe semi-automatic op `eiiitor has connected the cord circuit to the calli 1ine,.a cord finder :whose brushes are in' icated at 105 and 106 operates t'o coiinect anidle *sending device to the cord circuit taken for use.

When the seini-iilitoimitic operator conni-theooxd circuit to the calling line, she

asei'tliinsthe number of the Wanted suhsciibei: and' plroceeds to set this up on the ersending device.

t Vhas been VIlsslimed that 'the wanted number is ''-N. The operator Y will then de ress the corresponding stations, thoii s,fhiin1reds, tens and units keys iii response to which the associated sequence switch 're 'sters will be moved and the stetoiisiiegister 109 will `.come to rest in posi- This A tion 5.', the thousands register 110 will stop in position 4, the luiidreds register 111 in 'position 5, the tens register 112 iii position' 6 and the units register 113, iii position 7.

It will be assumed that the 'automatic trunk Selecting switch, whose brushes are indicated by tliegiumernls 107 and 108T lms been set to select theproper trunk for coiinecting the calling subscriber with the n fnamial operators lpositioir/in theolice in `which the wanted ine terminates. It will also be assumed that the sequence switch associated with this trunk selecting switch has been'inoved into position 1l.

After the sending device has h'een set and p'heir the trunk selecting switch has been operated to extend the calling`line to the manual operators position at the desired oiiice, tlie sequence switch associated with the cord finding-ull be in `position- 7, where "'a circuit will he established to move thescquciice sivitclrll out' of position l. This circuit muy be traced from grounded buttery, magnet of the sequence switch 114, con- .,tact 115, Contact y116 of the cord finder se- I, quei'ice switch to ground. When sequence 'switch 114 is in position 2, april-cuit is closed from ground; winding of reiiiy H7, sequence switch Contact ,118, cord finder brush ,105,.

contact 119, trun'k selector brush 108, lower armature and hack Contact of relay 120, winding 121 of thetrcpeating coil, winding of relay 123 to grounded battery. Relays 11i and 128 are operated by current. flowing over ,this circuit, At the armature and front Contact of relay 11T, a circuit is closed to ground through contact 124, mae'net of the sequence switch 114 to,grounded battery, to move this sequence switch out of position andinto position 3. At the front Contact and armature of relay 123, a circuit is closed from Iground through the lefbhand back contactr and armature of rela)Y 125, lamp 120 to grounded battery. Lamp 126, in lighting, iudicateel to the manual nierator that a call is waiting attention, and also indicates the trunk over which the. call has been extended. The manual operator thereupon presses key 1:37 to assoriate the number indicating device with theV trunk over which the call has been extended.

Upon the depression of key 12? a circuit is cloeed from ground, winding of rela)Y 120,

contact of key 127, conductor 12S, winding of relay :200 to grounded battery. Relay :00 attracts it armature. Hela) 120 at tracts is armatures, 'and its lower armature and hack contact interrupts the energizing circuit of relay 11i'. vWhen thi,` relay deencrgizcs, it closes a circuit from groiu'id, ita armature and hack Contact, contact 121), magnet ot' sequence switch 114 to grounded battery, to more sequence -witch 114 out of position 3 and through its various opel-ating poaitioue` back to position 1. during which a complete eet of code impulses is transmitted to the rela 201. 2014 and '203.

it will be assumed that a po itive impulse is transmitted in thc 'iull numbered positions oi' aequeuce switch 114. that'ia4 when the lead 130 is connected through the e quence switch contact 11323. and that a negative impulse is transmitted in the tractionally numbered position4 ot sequence switch 114. that is when the `lead 130 is connected through the .sequence switch contact lili). Thus. in position l. ot' sequence switch 114. no impulse is transmitted since there is no connection between grounded battery through the contacta ol' aeipience Iwitch 10.) to the lead 130. ln poeiition 4i. howerer..a

' circuit will be established Jfrom grounded battery; the reuirstance 143. equeuce Switch contact. ,131, l cqnence switch contact 132 to the lead 1110. thence through the sequence switch contact 130. brush 10.0. sequence .switch contact 12J. bruah 10T. upper armature and fr ont contact of relay'120, conductor .102, relayI 201, relay 202. relay 203.' con ductor 134. lower armature and t'ront contact 140 to ground, thus, producing a light impulse of negative current. Such impulses will cause the actuation of relay '903, wherebya circuit is established fronnground, varmature andicontuct of relay- 203, master s'wteh arm 226 and its first position contact, Winding of magnet 205 to grounded battery. Magnet 205 steps the positive lamp arm 215 to its second position contact.

In-lposition 5 of sequence szwitch 114, a circuit is established from grounded battery, the resistance 142, sequence switch contact, 138, `sequence switch Contact 141 to conductor 130, thence through seouenee switch contact 133, brush 105 and over the circuit described to brush106, sequence switch Contact 130 to ground, thus producing a light i1upulse of positive current. Such impulse operates the relay 202, wherebya circuit is established from ground, armature and con' tact oi' the rela)v 202, master .switch arm 227 and its first position contact. tho winding of magnet 200 to groundedlbattery. Magnet 206 steps the negative lamp arm 216 t its second position contact. i

In position 5?., a circuit is establiahed from grounded battery, resistanee-142, Sequence :switch contact 143, sequence switchjcontact 144 to the conductor 130, thence through sequence switch contact `139, brush 106, over the circuit. previously described to brush 105, sequence swite'h contact 140 toaground, thus producing a second'impulse ot' light negav tire current, and causing the positive lalnp arm 215 to be moved t0 its third position.

'In position G of sequence switch 114, a cir cuit. is established from grounded battery,

.` Sequence siiitch contact 145. sequence Switch contactv 140 to the conductor 130, thence through Sequence switch contact 153. brush 105 'over the circuit described to brush 106, A equencc switch? contact 136 to ground, thus producing an impulse of hear)v positive current. Such heavy positive current energizes both relay.: 201 and 202. Relay` :202 causes the energlzation ot' magnet Q00 whereby the negative lamp arm 210 is stepped to ita third position. The energization of relay 201 establishes a circuit from ground, the armature and front contact of relay 201. relay 228 to grounded battery, whereby relay 22S is energized and locked through ite inner armature and frontI contact to' the ground at the normal Contact 'of relay '229. In position 6.1 of sequence 4switch 114, no impulse is Sent over this circuit, hence the relays 201 to 203 are denergized. llpon the denergization of relay 201. a circuit is established from ground. the armature and back contact. of relay Q01. the outer armature and contact of relay 228, the Winding of relay 229 to grounded battery. Relay 229 becomes energized in this circuit and transfers the ground at its normal Contact from the winding of relay 22S to the Winding" of the master switch magnet 204. Master YLenawee Switch magnet 204 thereupon steps its arms 226, 227 and 230 to their second position contacts, which brin tbe magnets 207 and' 208 underthe contro of .relays 203 and 202 res ectively.

n this Vmannen' the positive and negative lamp armsar'each stepped to the proper position suchV as shown, for exam le, in the tablev hereinbefore provided.- pon 'the last heavy impulse of negative current in position ,17% ,osequence switch 114, the master switch magnet 204 steps its arms 22.6, 227 and`230 to. their sixth position, whereupon a circuit is established from ground, the sixth osition contact of arm 230, the normalle t-hand contact of .relay 225, left-hand windin of relay '225 to bat tery and round.` Re ay 225' becomes energizedy an throughA its inner right-hand armaturev` iocks up to the ground provided on th'e armature and contact of relay 200.`

Asrelay 225 attracts its armatures, a circuit is Stablished from ground, the arm 230 in its. sixth position, the alternate lefthand Contact of relay 225, the contact and armature of magnet 204, Winding of magnet 204 to battery and ground. Magnet 204 is ener gized in this circuit and steps the arms 226, 227 and. 230 to their first or normal position. Relay 225, however, remains energized as lon as relay200 remains energized. At tige and contact of' relayr 225, ground is placed on the conductor .ending to the positive lamp arms, whereby the circuit for the selectcd lamps is completed. For instance, stations lamp' W is Yincluded in a circuit from ground, the outer right-hand armature and contact of relay 225, the positive lamp arm 215 and its thirdposition contact, the lamp W, the negative lamp arm 216 and its third position contact to battery and ground. Y

The operator upon comprehcnding the Asignal displayed by thedii'erent lamps, releases the key 127. whereby the ,circuit inv cludinp relays 120 and 200 is broken and these relays become deiinergized. The de energizetion of relay 200 causes in turn the denergization of rela;r 225, and in-turn the opening of the circuit for the supply of current to the indicating lamps. Relay 200 also at its back contact closes a circuit to restore the switches controlled by magnets 205- to 214 inclusive to their first positions. The arms of magnets 214 being in position two, a vcircuit is established fron; ground, the armature and back contact of relay 200., the 111111231 and its second position contact, the contact and xii-mature of magnet 2M, finding of magnet 21:4 to battery and ground. Magnet 214 becomes energized and. being included in a self-interrupting circuit, steps its arms to their first `or norouter' right-hand armature` 200, the arm 231, the arm* 232 and its 4third position Contact, contact..

and armature of magnet 213windin net 2137to battery and round, w ereupon magnetii213 being inclu ed in a self-interrupting circuit moves its brushes to their first or noi-mall positions. vLikewise each one of the magnets 2.12 to 205 inclusive 4move their arms to their normal positionsl in turn until the whole'indicating device is returned to its normal position.

As the operator releases the kef127 `she places the lng 161 into the jack 162 of the wanted su scribers line, whereupon relay 125 becomes actuated. Y

It will be understood 'that as the impulse transmitting device 114 completes its operation, the' cord finder whose brushes are designated by the, characters 105 and 106, as well as the associated sequence switch, is restored to normal. At the same time the sequence switch, conta-cts of which are shown associated with ,the 'trunk selecting switch, is moved out of positio'n 11 to open the contacts 119 and 135 and to close the contacts 164 and 165.-. Relay 123 is non' energized as a calling supervisory relay and hence the lam 126 is not included 1n an effective circui The operator at` the manual position non' depresses the proper button of the key 163 to ring the station W on the selected lme.

At the close of the conversation, when the calling subscriber hangs up his receiver a signal (not shown) is operated at the semi-automatic operators position, and the operator proceeds to release the trunk selecting switch or other selecting switches employed in the connection. When these switches are released, the circuit ofA relay 123 .is opened and the lamp 126 is lighted to inform the manual operator that the call has terminated. This operator thenV re.

moves plug 161 from jack 162.

Attention is directed to the circuit arrangement of the signal lamps and the positire and negative lamp arms. It will be noticed that a maximum of four steps of these arms is employed to separately include each of.the lamps in an effective circuit. This may be clearly shown the folof maglowing table-1 ("olumnV 1 is a tabulation of the lamps. (lolurnn 2 is a tabulation of the positions of the positive lamp arm. Column 3 is a tabulation of the positions of the 4negative lamp arm. Column 4 is a tabulation of the number of steps taken by the positive lamp arm. Column 5 1s a tabulation of the number of steps talzen. by the negative lamp arm. Column 6 1s a tabula.- tion of the total number of steps taken' by the two switches. Since the lamp arms normlly rest in their first positions, the numbar of steps teken is always one less than the number of the position in which they come to rest.

l l PDS l l pos. of Steps Steps intel Limp. nikon by 1, taken h1; i sti` ,s 'Hum' "lrm i +arm. y umn l takiin.

E t I *en o n 1 5 i ,l o i l l 2 i l 1 l 2 :l` 1 2A l o 2 s 2 2 1 i i 2 4 1 a o l 2 1 2 s a 1 l a l o l a 3 2 1 2 l 1 3 7 2 .i i i 2 l 3 8 3 3 f 2 2 i 4 9 4 2 l 3 i I 4 Thus it will be seen that through u maximum of .four steps any one of the lamps me 1 be included in unl eil'ective circuit.

t is not necessary that this specific urrzingment be used, as the spirit of the invention is of broader scope and admits of manyi variations. u

It will he understood that this disclosure is merely typical of epplicants invention, und that its use is not limited to number indicating arrangements in automatic telephone systems or even in telephone systems broadly.

What is claimed is:

1. In a signaling system, an indicating device compusin a plurality of signals and a plurelit of se eetivelv operable step-hystep switc es, a selective y operable step-bystep switch tor controlling the sequence of operation of said first switches, a signaling circuit over which seid indicating device is controlled, und means for propagating and 4transmitting impulses ot' certain characteristics to control said first switches and for propagating und transmitting impulses of other characteristics to control sind second switch.

2. In al signaling system, an indicating device comprising a plurality of signalsnnd :i plurality of selectively operable step-bystep switches for controlling snid signals, ay

selectively operable step-by-stcp switch for controllin f the sequence of operation of said first switc es, a signaling circuit over which said indicating device is controlled, means for propagating und transmitting impulses of certain characteristics to cont-rol snid first switches, and Al'or simultaneously prop. ngating und trunsifnittingr impulses ot' other churawteristics to control said second switch.

In i1 signaling system, en indicating device comprising a plurality oi' signals und :1 plurulit of selectively operable step-by step switches for controlling seid signals, a selectively operable step-liys'tep switch for controllingr the sequence of operation of suid lirst switch, n signaling circuit over which said indicating device is controlled, and

i dicetin ycircuit over which seid indicating device is controlled, und means for propagating and simultaneously transmittingone series of impulses to control said first switches, and a second 'series of impulses for controlling said second switch.

5. In a signaling system, an indicating device comprismga plurality of indicating sig nn]s,.a plurality of selectivel operating stepby-step switches for control ing signals, a selectively operable step-b -Step switch for controlling seid first syvitc es, a. signaling circuit over which said indicating device is controlled, and means `for props,- gnting and transmittin a discontinuous series of impulses of various characteristics for controlling said indicating device.

6. In u si uling system, :1n indicating de vice comprising u plurality of sets o inlamps, a plurality of selectively operah e step-by-'step switches individual to each said 'set of lamps, a selectively operable step-bystep switch common to said set of lamps, a slgnaling circuit over which said Vindicating device is controlled, and means afor pro ngating and trsnsmittinga series.

of impu ses for controlling said mdicsting device. Y

7. In a signaling system, un indicating de vice comprising a.plurulity of sets of indicating lumps, two'sel `tively perablesstephystep switches indllifidual to cach said set of lumps, a si naling circuit over which said indicating evice is controlled, endl Ineens for propagating and transmitting a series of impulses for controlling said indicnting device. i

8. In a signaling system, nu indicating device comprlsing a set of indicating lamps for each character to be indicated, n pair of selectivelyr operable step-by-step switches individuel to each said set of lamps for selectively includingr e single one of said lamps in an effective circuit., a signaling circuit over which said indi'uting device is con trollcd, und menus for controlling said switches over said circuit.

9. In s signaling system, nn indicating device comprising a set of indicating lamps for cach character to be indicated. n` pair of selectively operable step-bystep switches for selectively including :my one of seid' und transmitting a 5 each of said controlled, und means for controlling in sequence oversaid circuit each said pair of switches. t

410. In a. signaling system, a set of signals, 5 a air of swltches for selectivel including said signals in anetective circuit, each said switch comprisin a series of contacts `less in number than tie nulnbei1 of. si nuls, and a Wipeifor copel'ating nitli sai( contacts, said signals bein included in cli'ective circuits when the Wipers of Said switches are coperating with their contacts in various combinations.

11. In a signaling system, n set of signals, 15 a air of switches for selectively includinvr said signals in an ,effective circuit, each sai 1 switch comprisin in number than tie number of si nuls, and n wiper for coperating with sai contacts, 20 said signals being included in effective cira series 'of contacts less cuits when the wi ers of said switches are coperatin with t 'eil' contacts subtantially a describe 12. In a signaling system, a set of ten signals, two switches for selectively including said signals in an eiective circuit, each said switch` comprising a series of eiective stationary contacts including e normal contact less in number than the number of lamps, and a Wiper for coperating with said contacts, means for moving said wipers over said contacts, said signals being so connected to ,said contacts that a maximum of four steps taken by said switches will separately include each of said signals in an effective circuit. v

In witness whereof, I hereunto subscribe my name this 30th day of January, A. D.,

TU DOR VAN AMSTEL. 

